A displacement pump includes an electrically powered drive having a drive housing. The drive is at least partially disposed in the drive housing and is configured to provide reciprocating linear motion to a diaphragm. The diaphragm is captured between an adaptor mountable to the drive housing and a fluid cover. The adaptor includes an inner mounting portion interfacing with the drive housing and an outer mounting portion interfacing with the diaphragm. Multiple adaptors having multiple outer mounting portion diameters can be mounted to the same drive housing. Each of the multiple adaptors have the same inner mounting portion configuration to mount to the same drive housing. The adaptors can FIG. 1B mount to the drive housing in multiple orientations while the fluid cover can mount to the adaptor in a single orientation